In the practice of dentistry, as well as in some aspects of medical practice, it is necessary to mix certain components to produce a mixed product useful for various purposes. Certain types of cement and filling materials fall in this category and, the production of a viscous mix of several ingredients to form impression material in the practice of dentistry for the production of various types of artificial dental appliances and the like is another category in which mixed materials are employed. For many years, materials of this type were mixed in mixing containers manually and, more recently, devices have been developed capable of accepting the necessary ingredients for a certain product and mixing, as well as dispensing the same from a device in which so-called static mixing units or mechanisms accomplish the mixing of the ingredients incident to being discharged from a nozzle, for example.
Examples of such static mixing devices as have been developed previously are represented in certain prior U.S. Patents of which the following are outstanding examples thereof:
U.S. Pat. No. 3,286,992--Armeniades et al--Nov. 22, 1966 PA0 U.S. Pat. No. 3,862,022--Hermann--Jan. 21, 1975 PA0 U.S. Pat. No. 3,923,288--King--Dec. 2, 1975 PA0 U.S. Pat. No. 4,183,682--Lieffers--Jan. 15, 1980 PA0 U.S. Pat. No. 4,207,009--Glocker--June 10, 1980 PA0 U.S. Pat. No. 4,538,920--Drake--Sept. 3, 1985
In the main, the foregoing patents are directed to the details of the static mixing units and supposedly comprise improvements in the capabilities of the mixing elements facilitating the intermixing of two or more ingredients. All of them have only a single elongated mixing unit through which the material passes once and then is considered to be mixed. Few of them show the source of the materials which are introduced into the static mixing units, with the exception of U.S. Pat. No. 4,538,920, in which it is seen that a pair of cylindrical containers are mounted in side-by-side relationship and the outlets merge into a common static mixing unit, the cylinders employing plunger members to effect discharge from the cylinders into the mixing unit.
It is the primary object of the present invention to improve the mixing of at least two ingredients more thoroughly than contemplated by the prior art and in a very simplified manner, details of the structure which accomplishes this being set forth below: